| 摘要 |
PURPOSE:To enhance developing speed and to obtain a superior image by treating a lithographic plate requiring no dampening water made of o-naphthoquinone-1,2- sulfonate or the like of a novolak resin, with a soln. contg. a specified alcohol before exposure. CONSTITUTION:A photosensitive layer made of naphthoquinone-1,2-diazide-5- sulfonate or 4-sulfonate of a novolak resin having 35-65% esterification rate is formed on a support of a chemically treated aluminum plate or the like. Said layer is coated with a silicone rubber layer to form a lithographic plate requiring no dampening water. Before exposure, this plate is held in the vapor of at least one kind of CnH2n+1OH (n is 1-5) aliphatic alcohol or a mixture of this and water for about 10min. or immersed in that liquid or treated otherwise. After exposure, it is immersed in a developing soln., and developed by rubbing it with a pat. A superior image free from pin-holes, cracks, etc. is obtained in a time shorter than the conventional ones. |
